Bran Stark made a horrible mistake on Sunday night's Game of Thrones, but in doing so, he irrevocably changed the game as we know it. Time is a flat circle, and of course Bran is the key to it all.

[Warning: major spoilers from Sunday night's episode of Game of Thrones ("The Door") lie ahead.]

Remember when I told you to stop sleeping on Bran? Well, I meant it. Love him or hate him, it's obvious that Bran's connection to the overall tale of ice and fire is more integral than anyone ever anticipated. Bran's ability to travel through time is a powerful tool, and as we witnessed in "The Door," his actions have an immense impact on the present. Case in point: Hodor.

Oh, Hodor. Or should I say Wyllis? You poor, big beautiful soul. You didn't deserve what happened to you.

At the end of the dramatic hour, Bran's longtime companion sacrificed himself to save Bran and Meera from a nasty horde of wights. Hodor held the door while they escaped, hopefully giving them enough time to get a substantial lead. But his death wasn't a surprise; it was fate.

When we saw a verbose young stableboy named Wyllis in Bran's vision of the past earlier this season, we knew the story of how Hodor became Hodor was going to be important, but we had no idea it would reveal a delicate time loop. ***GENRE FICTION ALERT***

As Bran travelled back in time to Hodor's youth in Winterfell, the combination of his time-travel magic and Meera's frantic cries for Hodor to "hold the door" against the wights in the present timeline caused a devastating ripple effect for Wyllis. The brain-melting seizure left him only able to say one word for the rest of his life: "Hodor."

TL;DR: Every time Bran has one of his visions, it creates a time bridge, connecting present Bran to the past. When Bran warged into Hodor in the present, he did so while observing the past, which then caused young Wyllis to seize and connect with his future self. So when Meera told Hodor to "hold the door," young Wyllis received the message. Hold the door = Hodor.

So again, let me reiterate: Bran is the catalyst to the past, present, and future -- and that makes him the most powerful MF in all of Westeros. And since he got himself marked by the Night's King, he's also the guy responsible for inevitably bringing down the Wall (sorry, Edd!) and the wights' long-awaited invasion on Westeros. See? Bran makes stuff happen!

Remember when he cried out to his father at the Tower of Joy? In George R.R. Martin's A Dance With Dragons, it's implied that he hears a whisper on the wind, but the show seemed to imply something more. If the Night's King was able to reach out and mark Bran, then who's to say Ned Stark didn't hear his young son at the tower? What other time loops has Bran created? Has Bran been unknowingly manipulating everything from the jump?

Earlier in the season, the Three-Eyed Raven told Bran the nature of his abilities. "We watch, we listen, and we remember. The past is already written. The ink is dry," he said. Unless, it's not. Bran might not have changed the past, but it did close a time loop, one that he created. So yes, Bran does have the power to change the past, but only in a way that leads to the present outcome. Theoretically, Bran can be responsible for anything and everything. (I don't think it's a coincidence that Bran's namesake is Bran The Builder, the founder of House Stark and the man responsible for constructing The Wall.)

The direct comparisons to Lost are not lost on showrunners David Benioff and D.B. Weiss. In fact, "The Door" was directed by Jack Bender, the same man who directed "The Constant" episode on Lost, the time-travel drama that became bogged down by its own mythology. And there are similar concerns when it comes to Game of Thrones. How can a show that already features dragons, wights, children of the forest, and magic now incorporate time travel?

Martin has always been candid about his intentions to subvert fantasy genre tropes in A Song of Ice and Fire, so those hoping for a happy ending should look elsewhere. And those hoping for a simple tale of wights v. dragons should know that Martin had a little something extra up his sleeve.

Time travel is messy and complicated, but it also leads to those kind of mind-fuck moments we've come to expect from Thrones. And remember: This is a show that brought Jon Snow back from the dead, so anything can happen.